I do a large percentage of my shopping online since taking six children to the store with me is... challenging. To say the least. I do prefer to touch and see in person before I buy but internet purchasing has other benefits such as lengthy descriptions, reviews, and comparison shopping.
I have recently been taking advantage of a few other online perks. I love to receive rebate deposits from sources like Ebates.com. MrRebates.com is another good resource for cash percentage back. I don't go looking for things to buy (that would defeat the purpose, no?) but when I have a need, I have often found cash back options or coupons from these sites. I am a member of both and check to see which has a better deal going when I'm ready to make a purchase. Combining these rebates with clearance sales or cash back credit cards on purchases adds up.
Another way to earn cash online is through Swagbucks. Points are earned using various features and traded in for prizes. For example, 450 points will buy a $5 gift card to Amazon.com. A lot of time could be waisted on this site trying to nickel and dime points with games and surveys but I simply utilize the search feature and earn slowly but surely.
I've mentioned MoneySavingMom before but she's worth mentioning again. For every 40 deals I pass up on her blog, there's always the one that makes it worth my time.
As I said, spending too much time with these kinds of sites can be wasteful, but after learning the ropes I am able to utilize them without throwing away my day. My combined earnings from the past several months will allow me to purchase my husband a birthday present this Summer without using his paycheck. It isn't usually that way but will be such a pleasure this time!
Finally, I recommend signing up for emails from retail stores you like to shop with... or even stores you wish you could shop with. You never know! I have set up a free email account just for these "junk" emails and browse them every few days to catch special sales. This was particularly helpful at Christmas time when I was able to find a few items for next to nothing with free shipping. Make the purchase through a rebate site and you'll find an even sweeter deal.